1. Technical Field
The present invention relates to a method of fabricating a semiconductor wafer, and an associated structure, for monitoring a temperature distribution across a surface of the wafer.
2. Related Art
Annealing or otherwise heating a semiconductor wafer at a uniform temperature in a range of 450-625xc2x0 C. may be required in a process that fabricates a semiconductor device. In order to ensure that a heating chamber used for the annealing is at the desired uniform temperature, particularly at a local space within the heating chamber at which the semiconductor wafer is positioned, it is necessary to monitor the temperature distribution within the local space of the heating chamber.
There is a known temperature monitor that can be used in the temperature range of 500xc2x0 C. to 625xc2x0 C. This known temperature monitor anneals a sputtered cobalt metal on silicon to form CoSi and CoSi2, and measures temperature variations in accordance with a stochiometry of the CoSi, the CoSi2, and an interfacial oxide. However, this known temperature monitor is difficult to use, since it requires two separate chemical stripping steps following the annealing. Another disadvantage is that this monitor is expensive to build and cannot be reused. Additionally, this monitor may not be sufficiently sensitive to the temperature distribution across the wafer, since the nonuniform sputtering of cobalt results in a wafer thickness variations from a center of the wafer to an edge of the wafer.
A simple method is needed for accurately monitoring a temperature distribution in a heating chamber in the 450-625xc2x0 C. temperature range.
The present invention provides a method for fabricating a semiconductor wafer, comprising the steps of:
providing a substrate that includes a semiconductor material having a first dopant;
forming an amorphous layer from a top portion of the substrate; and
doping the amorphous layer with a second dopant, wherein a polarity of the second dopant is opposite to a polarity of the first dopant.
The present invention provides a semiconductor wafer, comprising:
a substrate that includes a semiconductor material and a first dopant; and
an amorphous layer on the substrate, wherein the amorphous layer includes a second dopant, and wherein a polarity of the second dopant is opposite to a polarity of the first dopant.
The present invention provides a semiconductor wafer, comprising:
a substrate that includes a semiconductor material and a first dopant;
an amorphous layer coupled to the substrate, wherein the amorphous layer includes the semiconductor material and a second dopant, and wherein a polarity of the second dopant is opposite to a polarity of the first dopant; and
a crystal layer interposed between the amorphous layer and the substrate, wherein the crystal layer includes a crystal structure comprising the second dopant at a plurality of lattice points of the crystal structure.
The present method has the advantage of using a temperature monitor to accurately monitor a temperature distribution in a heating chamber in a 450-625xc2x0 C. temperature range. Additionally, the temperature monitor is reliable, easy to use, inexpensive to fabricate, and reusable.